Wing-scales of Pseudoleptocerus chirindensis Kimmins (Trichoptera: Leptoceridae)

The African species Pseudoleptocerus chirindensis belongs to a small group of Trichoptera most unusual in having scaly wings. Electron microscope studies reveal 13 structurally distinct kinds of cuticular process on the wings, including several types of squamiform and hair-like macrotrichia. These are described in detail and their possible functions inferred. The optical properties of the scales forming the colour pattern of the forewings are related to ultrastructural elements including diffraction and thin film interference systems. Trirhopteran scale structure is compared with that of the Lepidoptera, the sister-group in the Amphiesmenoptera. Differences are found and it is tentatively concluded that wing-scales have evolved independently in the two orders.